Cut tooth power transmission belt and blank for the same



May 9, 1944. R, Y, QASE y 2,348,522

CUT TOOTH POWER TRANSMISSION BELT AND BLANK FOR THE SAME original FiledMarch 13, 1 941 2 sheets-skin 1 ILE- l J 5 :Fissi- E i 7," ifi :TE-.Q 5-3 I INVENToR..

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',May's, 1944. l R CASE f 2,348,522

CUT TOOTH POWER TANSMISSION BELT AND BLANK FOR THE SAME Original IlledMarch i3, 1941 2 Sheets-Sheet 2 INVENTOR. "m ,was/,4 @a y. 0,4 si,

BY .A MM /k Arron/ver Patented May 9, 1944 AND BLANK FOR THE SAME pRichard Y. Case, Philadelphia, Pa., assignerv to L. H. Gilmer Co.,Tacony, Philadelphia, Pa., a corporation of New Jersey Y VOriginalapplication March 13, 1941, Serial No. 383,236. Divided' and thisapplication 'August 29, 1941, Serial N0.A408,880` l u loiaim. v(el.74-236) In V-belts, as heretofore made, the side driving walls of thebelt bulge in contacting the walls of the pulley whereby the said wallswear unevenly. The friction on these bulging walls is so great that theexcessive heat thereby generated has resulted in explosions in the belt,as a result oi which the belt is useless.

The primary object of my invention is to provide a power transmissionbelt which, regardless of its diameter, is adapted to run smoothly overpulleys of various diameter.

Another object of my invention is to provide a toothed belt in which theend walls of the teeth do not bulge when engaging the pulley over whichit is moving, thereby retaining a rm continuous contact from top tobottom with the end walls of the belt.

Another object of my invention is to provide a out toothed powertransmission belt adapted to be used on a dat or V-shaped pulley.

Another object of my invention is to provide a power transmission beltcomprising a plurality of cut teeth and a pulley, or neutral axissection, said section being molded and vulcanized with said teeth; andwith these, and other objects in view, my invention consists of theparts and combination of parts hereinafter set forth.

This is a division of my application led March 13, 1941, Serial No.383,236.

In the drawings: y

Figure 1 is a bottom plan View, the left hand portion of which shows thebelt body as originally molded and vulcanized, the righ hand portionshowing teeth cut from said body.

Figure 2 is a top plan view of Figure 1.

Figure 3 is a side elevation of Figure 2, portions being in section.

Figure 4 is a sectional View on the line 4 4, Figure 1.

Figure 5 is a sectional view on the line 5 5, Figure 1.

Figure 6 is a side elevation of a modied form of the belt partially insection.

Figure 7 is a sectional view on the line 1-1, Figure 6.

Figure 8 is a bottom plan View of the belt shown in Figures 6 and '7,partly broken away to expose the neutral zone section.

Figure 9 is a vertical longitudinal section of the belt showing indotted lines where cuts are to be made in the belt body to form theteeth.

Figure 10 shows the belt applied to a pulley.

The belt, according to my invention, is moulded as shown in Figure 5which is a transverse sectional view.

yThe pulling cable cords are designated by the reference numeral I ofwhich there may be one or a plurality of layers, accordingto the workthe belt is designed for. The cords are rubberized, or otherwisesuitably treated prior to their application in the belt, and theyconstitute the neutral axis and pulling section of the belt.

The cords l are then embedded in a mass of comparatively soft rubber 2,which entirely surrounds the cords, as shown, to prevent frictionbetween the cords and to enable the cords to readily bend around apulley.

The cords l and soft rubber 2 are then enclosed in a casing, or cover,3, of a material designed to vulcanize hard, or comparatively hard; thusafter the assembly of the parts shown in the drawings is properlyvulcanized it becomes a substantially rigid structure, which ispractically non-ilexible throughout its length. It will be understood,of course, that the structure thus formed may be endless, or in lengths,as desired.

After the body is thus formed and vulcanized it is separated into teeth4 on the compression side of the belt and block-like members 4 on thetension side of the belt along the dotted lines 5 and 6. as shown inFigure 9, by cutting in any way found most desirable, but the cuttingstops short of the neutral axis structure of soft rubber 2 and cords l,as clearly shown in the drawings. words, the cuts 5 in the side wallsterminate at the side edges of the neutral axis structure, while thecuts 6 extend inwardly from the upper or outer surface of the belt andterminate at their inner ends at or adjacent to the outer surface of theneutral axis structure Without penetrating the same whereby the body isseparated into cut teeth throughout its length, while the neutral axisstructure remains continuous and integral throughout the belt.

This improved belt may be constructed as a at belt, as showrr in Figures1, 2, 3, 4 and 5, and if desired may be formed as an endlesssubstantially v -shaped belt, as shown in Figures 6, 7, 8, 9 and 10.

In both the flat and V belt the cuts from the bottom face of the beltare inclined as at l, thereby eliminating crowding or contact betweenthe teeth while passing over the pulley 8, as shown in Figure 10.

In the V belt structure I may cover the belt body in a rubberizedwrapper 9.

In all forms of belt, according to my invention, the teeth 4 and blocks4 are hard and non-flexible, whereby the durability of the belt isincreased and whereby the ends of the teeth are pre- In other ventedfrom bulging and the sides of the blocks from jamming in contacting withthe walls of the groove in a pulley, thereby insuring a rm continuouscontact from top to bottom of each tooth, in a V belt with the Walls ofthe groove of the pulley, thus materially reducing, if not entirelyeliminating, the generation of heat in the belt experienced in the Vbelts as heretofore constructed, thus prolonging the life of the belt.Thus the compression and tension sides of the belt formed respectivelyby the blocks and the teeth are hard and incompressible and ineXpansibleso as to provide a belt which is adapted for long wear and incapable ofdistortion in the manner mentioned,y whereby the noted objections toprior belts are avoided. In thisbelt, as each hard and incompressibletooth is arranged opposite to and in transverse alinement with a hardand incompressible block-like member, the belt can ex solely along thelines between adjacent pairs of blocks and teeth, so that the belt isadapted to run smoothly over pulleys of various diameters withoutbulging and becoming overheated.

What I claim is:

A cut tooth power transmission belt consisting of an elastic neutralzone section comprising one or more rows of inextensible pull cords, asoft rubber body in which said cords are invested, an inherently hardvulcanized material surrounding the top, bottom and sides of saidneutral zone section and inexible against compression or expansion andtransversely divided into a continuous series of block-like membersconstituting a continuous series of projecting teeth on the compressionside of the neutral zone section, and companion block members on thetension side of the neutral zone section, said tooth members arranged intransverse alignment with the companion block member and entirelyseparated from the adjacent teeth by intervening transverse divisionswhereby the belt is adapted to flex solely on the neutral Zone sectionon lines between the adjacent pairs of companion teeth in blocksections.Y

RICHARD Y. CASE.

